Functional microbial stimulation for oil recovery enhancement based on microbial community analysis

Abstract

This study stimulated functional microbial adaptation to the extreme environment of the Luliang oilfield reservoir and assessed the impact of indigenous microbial enhanced oil recovery treatment on the microbial community and oil recovery. By high-resolution pyro-sequencing, Acinetobacter, Pseudomonas, Sphingomonas, Thauera, Arcobacter and Hyphomonas were regarded as suitable candidates and a customised nutrient mixture was selected to activate the target microbes. The interfacial tension of crude oil and water decreased from 29.76 mN m À1 to 0.65 mN m À1 and the emulsion stability index increased from 5% to 92% after customised nutrient culture. The oil biodegradation experiments after the cultivation exhibited positive effects in degrading aromatics, resins and asphaltenes fractions and improving the mobility. Six target genera were activated markedly after 96 h of incubation. The oil recovery was enhanced from 51.2% to 60.7% using fermentation broth injection. Thus, injecting a customised nutrient mixture with injection brine into the stratum to stimulate functional microbes has the potential to enhance oil recovery in the Luliang oilfield.

Composition of Bacterial and Archaeal Communities in an Alkali-Surfactant-Polyacrylamide-Flooded Oil Reservoir and the Responses of Microcosms to Nutrients

“…To date, a large amount of microbial populations have been isolated or detected in oil reservoirs worldwide (Lenchi et al, 2013; Al-Sayegh et al, 2015; Gao et al, 2016; Okoro et al, 2016; Su et al, 2018). These microorganisms are versatile: some species can degrade crude oil, some can produce biosurfactants (Liu et al, 2015; Cui et al, 2017; Qi et al, 2018), biopolymers (Bi et al, 2016; Xia et al, 2018; Zhao et al, 2018), or biogases (Dong et al, 2015; Zhu et al, 2015), and have been used to mobilize and recover residual oil from oil-bearing rocks (Youssef et al, 2009; Wang et al, 2014; Yi et al, 2018). In addition, nitrate can be used to reduce formation of hydrogen sulfide produced by sulfate-reducing bacteria (SRB) based on the competitive inhibition of nitrate-reducing bacteria on SRB (Gieg et al, 2011; Gassara et al, 2015).…”

Exploiting Microbes in the Petroleum Field: Analyzing the Credibility of Microbial Enhanced Oil Recovery (MEOR)

“…), alkaliphilic (Natronococcus occultus), and thermophilic (Pyrolobus fumarii and Thermus aquaticus) bacteria and polyextremophiles (Halonatronum saccharophilum and Natranaerobius thermophilus) are the only microbes that are sufficiently small in size, can survive harsh environments (pH, temperature, salinity, pressure), and are capable of producing vital metabolic products [43][44][45][46]. For better adaptation to the surrounding oil environment, these hydrocarbon-consuming, non-virulent, and naturally occurring microbes are preferred and have attracted the attention of the researchers of MEOR [47][48][49].…”

Environmental conditions and diffusion-limited microbial transfer drive specific microbial communities detected at different sections in oil-production reservoir with water-flooding

“…Given the pronounced differences in inherent conditions among the reservoirs, in particular key microbial growth limiting factors, such as temperature (13,22), salinity (23,24), and pH (25), a variety of microbial ecological patterns with high variability in community composition have been identified in these ecosystems. Furthermore, studies are increasingly indicating that microbiologically-improved oil production processes are closely related to changes in the microbial communities of reservoirs, such as altered microbial abundance and composition (5,(26)(27)(28)(29). This is of great significance to the study of the microbial communities inhabiting petroleum reservoirs.…”